Polyester, polypropylene and polyethylene woven and non-woven fabrics have many applications for which their hydrophobic characteristics are undesirable. These include applications where a high ability to transmit water is desirable, such as for diapers, adult incontinence pads, agricultural fabrics for landscaping or mulching, and some filtration devices; applications where wicking away of moisture is desirable for comfort reasons, such as for certain clothing and sportswear purposes; and applications where it is desirable to make the surface of a fiber more hydrophilic for better adhesion or easier incorporation into water-borne compositions such as cement mixtures or paper pulps.
Polypropylene or polyethylene is commonly used as the liner (coverstock) in baby diapers and adult incontinence pads, and in these applications it is next to the wearer's skin. By design, moisture must pass through the polypropylene or polyethylene layer into the absorbent layer below. Since polypropylene or polyethylene is naturally hydrophobic, it must be treated to allow the moisture to pass through quickly and not run off the top of the diaper or pad.
In diaper manufacture in the U.S. the above liner is commonly treated with a small amount of a surfactant wetting agent, such as an alcohol ethoxylate, to improve moisture transport through the polypropylene or polyethylene layer. Since the alcohol ethoxylate is usually water soluble, it dissolves and reduces the surface tension of the water. This causes the moisture to wet the polypropylene or polyethylene and pass through more quickly. The use of an alcohol ethoxylate has two important drawbacks, however. Since it dissolves off, little remains to improve passage of any second or subsequent exposures to moisture. The capacity of the absorbent layer is reduced as well, since its absorptivity is based on capillary action, which is adversely affected by absorption of the alcohol ethoxylate.
A coating is needed which would allow moisture to pass through the polypropylene or polyethylene liner quickly, but that will not readily wash off. The present invention provides such a coating and a process for its application.
Polypropylene, polyethylene or polyester are also commonly used in generation of nonwovens used in protective garments such as medical, surgical, laboratory and other garments. Such garments can be uncomfortable due to poor hand and lack of moisture transport. A coating or treatment is needed which softens the nonwoven fabrics or fibers and wicks away moisture to enhance comfort. The present invention provides such a coating or treatment. Thus the compositions, methods, fabrics and fibers of the present invention are useful in clothing applications and other applications where improved wicking or moisture transport through a woven or non-woven fabric of polyester, polypropylene or polyethylene is important. Other potential applications include usage as a softener or soil release treatments for polypropylene, polyethylene, polyester, cotton, polyamide, or polyaramid garments and slickeners for polyester fiberfill.